Garden Talk: July 17, 2008

From NGA Editors

Outstanding Shrub for Late-Summer Color

Most flowering shrubs bloom from early spring to summer, and by the time July rolls around there arent many colorful shrubs other than crape myrtles and hydrangeas. But a relatively uncommon shrub from Korea and China is now becoming more widely available because of its late-season white flowers.

Campylotropis macrocarpa is a 4- to 5-foot-tall shrub from Korea and China that blooms from mid to late summer. This legume family shrub features a multitude of 3-inch purple and white bloom clusters with red centers. Campylotropis is a widely adapted, sun-loving, deciduous shrub thats hardy in USDA zones 5 to 9.

Compost Reduces Potato Diseases

Soilborne diseases, such as common scab and stem canker, can be a problem when growing potatoes, often ruining a potato patch. Recent research has focused on using beneficial microbes and compost as non-chemical alternatives for combating these diseases. The results have been promising.

Researchers at the University of Maine grew potatoes treated with two biological control agents and two types of compost to see if these treatments would significantly reduce the amount of disease on potatoes. The two compost treatments consisted of a conifer-based blend and a hardwood-based blend. The biological treatments included spraying Bacillus subtilis and a hypovirulent strain of Rhizoctonia solani on the patch.

All treatments reduced the incidence of stem canker by 27 to 50 percent compared to the control. The biological treatments and conifer-based compost reduced the incidence of common scab, but the hardwood-based compost increased the amount of the disease. Overall, the potato yield was 30 to 54 percent higher for all the treatments compared to the control plot.

Keep Cool in the Garden

Its hot outside, and in many parts of the country, plants as well as gardeners are wilting under the heat. Gardening in the hot sun at high temperatures can lead to sunburn, dehydration, and heat stroke. Gardeners can reduce the risks by working outside in the morning and evening when the temperature is lower; wearing light-colored, loose-fitting clothing; applying sunscreen and wearing a hat; and staying hydrated. However, if you find it too hot even under these conditions, try the new Cool Pouch.

The Cool Pouch is a cotton towel thats worn like a scarf. Developed by tennis pros, it has sleeves in the back where you can place 8 ounces of ice. The iced pouch sits at the back of your neck and cools the carotid arteries. The manufacturer claims that if these arteries stay cool, youll be able to function better in the heat and be less likely to suffer heat stress.

Favorite Perennial Book Just Got Better

Gardeners love a good reference book, and a favorite among perennial gardeners has been Allan Armitages Herbaceous Perennial Plants. Now a new edition has been released that promises to be even more entertaining and informative than its predecessor.

Herbaceous Perennial Plants, A Treatise on Their Identification, Culture, and Garden Attributes, Third Edition (Stipes Publishing, 2008; $68)is a big improvement over the previous edition. One of the drawbacks to the previous edition was the lack of photographs. Although Armitage has a witty and descriptive writing style, theres nothing more frustrating to a gardener than not being able to see the plants he raves about. The third edition has more than 300 photographs, along with hundreds of new plants. For the avid perennial gardener, its a must-have for identifying, selecting, and growing various perennial flowers. Theres even a scientific and common name index to help with identifying a favorite flower.